Don't wait to close tabs waiting for JavaScript dialogs.

content/browser/frame_host/render_frame_host_impl.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 918 matching lines @@
   bool is_waiting_for_beforeunload_ack_;
 
   // Valid only when is_waiting_for_beforeunload_ack_ or
   // IsWaitingForUnloadACK is true.  This tells us if the unload request
   // is for closing the entire tab ( = false), or only this RenderFrameHost in
   // the case of a navigation ( = true). Currently only cross-site navigations
   // require a beforeUnload/unload ACK.
   // PlzNavigate: all navigations require a beforeUnload ACK.
   bool unload_ack_is_for_navigation_;
 
+  // True while a JavaScript dialog is shown.
+  bool is_within_javascript_dialog_ = false;

[Charlie Reis, 2016/10/05 22:00:59]

Any chance the delegate knows if the dialog is showing, and we can just ask it
instead?  I'm not opposed to adding this bit if needed, but it would be nice to
avoid having even more state on RFH if possible.

+
   // Indicates whether this RenderFrameHost is in the process of loading a
   // document or not.
   bool is_loading_;
 
   // PlzNavigate
   // Used to track whether a commit is expected in this frame. Only used in
   // tests.
   bool pending_commit_;
 
   // The unique ID of the latest NavigationEntry that this RenderFrameHost is
@@ skipping 97 matching lines @@
 
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_